The present invention relates to an ultrasonic image display apparatus for displaying ultrasonic images based on echo signals from the three-dimensional region of a test object, and a control program for controlling the ultrasonic image display apparatus.
For example, blood vessels of the test object may be observed by ultrasonic diagnostic equipment using contrast images. It is useful to get an overall picture of the blood vessels running through, say, a tumor and its surroundings by means of blood vessel contrast image. However, since two-dimensional contrast image depicts only those blood vessels that are present on a specific cross section, it is difficult to obtain a three-dimensional overall picture of the blood vessels.
Given that difficulty, there exists ultrasonic diagnostic equipment that displays two-dimensional projection images based on projection data generated from echo signals of a plurality of frames, i.e., generated either from the data obtained by integrally adding up the echo signals of the plurality of frames acquired from the three-dimensional region of the test object, or from the data using maximum signal values of the echo signals of the plurality of frames (e.g., see Japanese Patent Publication No. 3365929).
The above-mentioned ultrasonic diagnostic equipment acquires the echo signals from the three-dimensional region of the test object by having an ultrasonic probe moved over the test object to transmit and receive ultrasonic waves thereto and therefrom. Since it is difficult to keep identical the velocity at which the operator moves the ultrasonic probe in different tests, the time required for the probe to move the same distance may differ from test to test.
Ordinarily, however, the range in which to obtain echo signals used for generating the above-mentioned projection data is set in accordance with the number of frames and the time involved. The frame count and the time are input by the operator and remain constant regardless of the moving velocity of the ultrasonic probe. This means that the range in which to obtain the echo signals used for generating the projection data (i.e., range of the ultrasonic probe in the direction of its movement) varies depending on the moving velocity of the ultrasonic probe. Thus if the moving velocity of the ultrasonic probe is low, it is impossible to acquire the projection data using the echo signals over a sufficient range, which may result in the display of a projection image showing the target blood vessels being truncated halfway.
In view of the problem above, there is a need for keeping constant the range in which to obtain the echo signals used for generating the projection data regardless of the variable moving velocity of the ultrasonic probe.